#define _CRT_SECURE_NO_WARNINGS 1
#include"string.h"
namespace bit
{
	const size_t string::npos = -1;
	void string::reserve(size_t n)
	{
		char* tmp = new char[n + 1];
		strcpy(tmp, _str);
		delete[]_str;
		tmp = _str;
		_capacity = n;

	}
	void string::push_back(char ch)
	{
		if (_size == _capacity)
		{
			reserve(_capacity == 0 ? 4 : _capacity * 2);

		}

		_str[_size] = ch;
		_size++;
	}
	void string::append(const char* str)
	{
		size_t len = strlen(str);
		if (_capacity = _size + len)
		{
			reserve(_capacity == _size + len ? _size + len : _capacity * 2);
		}
		strcpy(_str + _size, str);

		_size += len;
	}
	string& string::operator+=(char ch)
	{
		push_back(ch);
		return *this;
	}
	string& string::operator+=(const char* str)
	{
		append(str);
		return *this;
	}
	void string::insert(size_t pos, char ch)
	{
		assert(pos < _size);

		if (_size == _capacity)
		{
			reserve(_capacity == 0 ? 4 : _capacity * 2);
		}

		size_t end = _size + 1;
		while (end > pos)
		{
			_str[end] = _str[end - 1];
			--end;
		}

		_str[pos] = ch;
		++_size;
	}
	void string::insert(size_t pos, const char* str)
	{
		assert(pos < _size);

		size_t len = strlen(str);

		if (_capacity == _size)
		{
			reserve(_size + len == _capacity ? _size + len : _capacity * 2);
		}

		size_t end = _size + len;

		while (end > len+pos-1)
		{
			_str[end] = _str[end - len];
			--end;
		}

		for (size_t i = 0; i < len; i++)
		{
			_str[pos + i] = str[i];
		}

		_size += len;
	}
	void string::erase(size_t pos, size_t len)
	{
		assert(pos < _size);

		if (len > _size - pos)
		{
			_str[pos] = '\0';
			_size=pos;
		}
		else
		{
			for (size_t i = pos + len; i <= _size; i++)
			{
				_str[i - len] = _str[i];
			}

			_size -= len;
		}
	}
	size_t string::find(char ch, size_t pos)
	{
		assert(pos < _size);

		for (size_t i = pos; i++; i < _size)
		{
			if (_str[i] = ch)
			{
				return i;
			}
		}

		return npos;
	}
	size_t string::find(const char* str, size_t pos)
	{
		assert(pos < _size);
		
		const char* ptr = strstr(_str + pos, str);

		if (ptr == nullptr)
		{
			return npos;
		}
		else
		{
			return ptr - _str;	
		}
	}
	string string::substr(size_t pos, size_t len)
	{
		assert(pos < _size);

		if (len > _size - pos)
		{
			len = _size - pos;
		}

		string sub;
		sub.reserve(len);
		for (size_t i = 0; i < len; i++)
		{
			sub += _str[pos + i];
		}

		return sub;
	}
	bool operator<(const string& s1, const string& s2)
	{
		return strcmp(s1.c_str(), s2.c_str()) < 0;
	}
	bool operator<=(const string& s1, const string& s2)
	{
		return s1 < s2 || s1 == s2;
	}

	bool operator>(const string& s1, const string& s2)
	{
		return !(s1 <= s2);
	}

	bool operator>=(const string& s1, const string& s2)
	{
		return !(s1 < s2);
	}

	bool operator==(const string& s1, const string& s2)
	{
		return strcmp(s1.c_str(), s2.c_str()) == 0;
	}

	bool operator!=(const string& s1, const string& s2)
	{
		return !(s1 == s2);
	}
}

